- Laser-Triangulation
- GigE-Vision und GenICam
- HDR-3D
- Automatic AOI-Tracking
The Principle of Laser-Triangulation or Sheet of Light
In this 3d measuring method, a laser beam is directed via a line lens onto the surface of the object to be measured. With the help of a CX camera, a picture of the laser line is acquired from the triangulation angle alpha. As a result of the arrangement of the laser and the camera, any change in the surface make-up below the laser line will lead to the laser line in the camera image being displaced in a defined manner.
The task of a CX camera is to use maximum speed and precision to determine the position of the laser line. Below, you will see a number of typical laser-scanning arrangements. For the approximation of the height resolution data that has been given, the following symbols have been used: dX= resolution along the laser line, dY= resolution perpendicular to the laser line (in the direction in which the object or the camera moves), dZ= resolution in the direction of height.
CX sensor technology uses the interface standard, GigE-Vision, and the generic software interface, GenICam. Both protocols are destined to become the standard for vision sensors in future. The GigE-Vision standard defines a uniform communications protocol based on UDP/IP, via which GigE Vision-compatible devices can communicate with an imaging unit (PC).
The GenICam software standard is a universal software interface providing a description of the functions of vision sensors. This makes it possible to run vision sensors using generic software, as well as access the sensor parameters. An XML protocol is used for this purpose. The combination of GigE-Vision and GenICam enables the operation of Vision devices via device-independent software. Not only does this make the integration and exchange of Vision equipment considerably easier, it also keeps development costs low.
- The use of Ethernet, the ready-for-market technology, with its extensive yet value-for-money range of components, such as standard industrial connectors, network cards, switches, etc.
- The use of long connection cables up to 100 metres for copper lines. Longer distances can be covered with optical waveguide lines.
- The option of running any amount of Vision devices on one imaging unit
- The integral remote-maintenance function
- The realisation of a concept for distributed computing is made easier.
- The independence of the underlying transport medium, enabling the use of future protocols such as 10 Gbit-Ethernet.
- GigE-Vision and Genicam are supported by the main Vision suppliers (e.g. National Instruments, Matrox, Dalsa, Photonfocus, Pleora Technologies, Stemmer Imaging, MVTec and others).
Principle of high Dynamic Range (HDR) measuring
With the development of the C4-1280-GigE 3D camera, AT has added a new dimension when it comes to 3D measurement options using laser triangulation. With the help of new HDR-3D (High Dynamic Range) functionality, it is now possible to scan materials and surfaces with inhomogeneous reflection properties. The recording of saturated intensity readings is now a thing of the past because HDR-3D expands the dynamics of image intensity up to 90dB.
Essentially, HDR-3D comprises two independent but combinable sensor functions:
The aim of the MultipleSlope function is to avoid the saturation of pixels during sensor chip exposure. To do this, the threshold values for the recorded light volume and the voltage produced are set. If, within a predefined time, the threshold is exceeded the voltage of the pixel is reset to the threshold value. Next, the light exposure is continued until the exposure is complete. This mode is known as DualSlope. There is also an option of resetting the pixel voltage after the first reset (TripleSlope mode). The reset level and reset times in DualSlope and TripleSlope mode can be configured independently of one another.
The Non-Destructive Readout (NDR) function makes multiple sensor-chip readout possible during the exposure time without having to reset the pixels. Up to 7 readouts are possible. To this end, the time for each readout is predefined. This makes it possible to read out the recording of highly reflective objects shortly after the start of the exposure, the image of darker areas being read at the end of the integration time. When combining part records, a homogenous, saturation-free image can be generated.
Interleaved-Shutter
Sequential-Shutter
“Automatic AOI-Tracking” for fast 3D Imaging
Our high-speed 3D cameras of the C4 Series are, as of now, available with a new firmware that enables faster surface scanning.
Thanks to a new sophisticated algorithm for the automatic fitting and tracking of AOIs, the size of an AOI can now be reduced to a minimum amount of rows, enabling a considerable increase in scanning speed. This new feature is particularly interesting for applications involving continuous profile measurements with variable distances to the surface. This way, this new feature enables our customers to take the most advantage of the full potential of their 3D cameras and get precise 3D images at an even higher speed.